Atherectomy devices and methods

ABSTRACT

Rotational atherectomy devices and systems can remove or reduce stenotic lesions in blood vessels by rotating one or more abrasive elements within the vessel. The abrasive elements are attached to a distal portion of an elongate flexible drive shaft that extends from a handle assembly that includes a driver for rotating the drive shaft. In particular implementations, the handle assembly encapsulates an electric motor assembly, a pump assembly, and a controller assembly.

CLAIM OF PRIORITY

This is a continuation of U.S. application Ser. No. 18/094,010, filed onJan. 6, 2023, which is a continuation of U.S. application Ser. No.18/150,369 filed on Jan. 5, 2023, which is a continuation of U.S.application Ser. No. 17/592,797 filed on Feb. 4, 2022, which is acontinuation of U.S. application Ser. No. 16/530,284 filed on Aug. 2,2019 (now U.S. Pat. No. 11,272,954), which claims the benefit of U.S.Provisional Patent Application Ser. No. 62/715,643 filed on Aug. 7,2018, the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

This document relates to rotational atherectomy devices and systems withan electric motor that removes or reduces stenotic lesions in bloodvessels, for example, by rotating an abrasive element within the vesselto partially or completely remove the stenotic lesion material.

BACKGROUND

Atherosclerosis, the clogging of arteries with plaque, is often a resultof coronary heart disease or vascular problems in other regions of thebody. Plaque is made up of fat, cholesterol, calcium, and othersubstances found in the blood. Over time, the plaque hardens and narrowsthe arteries. This limits the flow of oxygen-rich blood to organs andother parts of the body.

Blood flow through the peripheral arteries (e.g., carotid, iliac,femoral, renal etc.), can be similarly affected by the development ofatherosclerotic blockages. Peripheral artery disease (PAD) can beserious because without adequate blood flow, the kidneys, legs, arms,and feet may suffer irreversible damage. Left untreated, the tissue candie or harbor infection.

One method of removing or reducing such blockages in blood vessels isknown as rotational atherectomy. In some implementations, a drive shaftcarrying an abrasive burr or other abrasive surface (e.g., formed fromdiamond grit or diamond particles) rotates at a high speed within thevessel, and the clinician operator slowly advances the atherectomydevice distally so that the abrasive burr scrapes against the occludinglesion and disintegrates it, reducing the occlusion and improving theblood flow through the vessel.

SUMMARY

Some embodiments of a rotational atherectomy device for removingstenotic lesion material from a blood vessel of a patient, includes: anelongate flexible drive shaft; an abrasive element coupled to a distalportion of the elongate flexible drive shaft; and a handle comprising anouter housing. The handle further includes an electric motor coupled toa proximal portion of the elongate flexible drive shaft, where theelectric motor can be configured to cause rotation of the elongateflexible drive shaft in a first rotational direction. The device alsoincludes a pump configured to provide fluid to a distal portion of theelongate flexible drive shaft, wherein the outer housing contains theelectric motor and the pump.

In some embodiments, the rotational atherectomy device further comprisesa control system configured to control rotation of the electric motor bymonitoring an amount of current supplied to the electric motor andlimiting the amount of current supplied such that the amount of currentdoes not exceed a threshold current value. In some embodiments, thecontrol system is configured to control rotation of the electric motorby initiating a stopping protocol when the amount of the currentsupplied reaches a threshold current value. In some embodiments, thestopping protocol comprises reducing the amount of current supplied tothe electric motor to approximately zero. In some embodiments, thestopping protocol comprises reversing rotation of the elongate driveshaft by reversing the rotation caused by the electrical motor from thefirst rotational direction to a second rotational direction. In someembodiments, the stopping protocol occurs after a predetermined amountof time. In some embodiments, the predetermined amount of time is about0.1 second to about 60 seconds. In some embodiments, the predeterminedamount of time begins after the threshold current value is reached. Insome embodiments, the elongate flexible drive shaft defines alongitudinal axis and comprising a torque-transmitting coil of one ormore filars that are helically wound around the longitudinal axis in asecond rotational direction, such that rotation of the elongate flexibledrive shaft in the first rotational direction causes unwinding of theone or more filars of the elongate flexible drive shaft.

In some embodiments, the device further comprises a power sourceconfigured to couple to the handle. In some embodiments, the devicefurther comprises a rechargeable battery removably coupled to thehandle. In some embodiments, the handle further comprises a battery. Insome embodiments, the handle further comprises a pump motor coupled tothe pump and configured to run the pump. In some embodiments, the pumpcomprises at least one of a micropump, a piezoelectric pump, anelectromechanical integrated pump, a peristaltic pump, or aquasiperistaltic pump. In some embodiments, the electric motor comprisesat least one of a DC motor, or a DC motor controller. In someembodiments, the elongate flexible drive shaft is directly coupled tothe electric motor. In some embodiments, the elongate flexible driveshaft is directly coupled to the electric motor via a cannulation in theelectric motor. In some embodiments, the electric motor is coupled tothe elongate flexible drive shaft in a gearless configuration. In someembodiments, the elongate flexible drive shaft is coupled to theelectric motor via one or more gears. In some embodiments, the gearratio is 2:1.

In some embodiments, a rotational atherectomy device for removingstenotic lesion material from a blood vessel of a patient, includes: anelongate flexible drive shaft defining a longitudinal axis andcomprising a torque-transmitting coil; an abrasive element coupled to adistal portion of the elongate flexible drive shaft; and a handle. Thehandle comprises: an electric motor coupled to a proximal portion of theelongate flexible drive shaft, the electric motor configured to causerotation of the elongate flexible drive shaft in a first rotationaldirection, such that rotation of the elongate flexible drive shaft inthe first rotational direction causes unwinding of the elongate flexibledrive shaft; and a control system configured to control rotation of theelectric motor by monitoring an amount of current supplied to theelectric motor; and limiting the amount of current supplied such thatthe amount of the current does not exceed a threshold current value.

In some embodiments, the torque-transmitting coil includes one or morefilars that are helically wound around the longitudinal axis in a secondrotational direction. In some embodiments, the control system isconfigured to control rotation of the electric motor by initiating astopping protocol when the amount of the current supplied reaches athreshold current value. In some embodiments, the stopping protocolcomprises reducing the amount of current supplied to the electric motorto approximately zero. In some embodiments, the stopping protocolcomprises reversing rotation of the elongate drive shaft from the firstrotational direction to the second rotational direction. In someembodiments, the device further comprises a power source configured tocouple to the handle. In some embodiments, the device further comprisesa rechargeable battery removably coupled to the handle. In someembodiments, the handle further comprises a battery. In someembodiments, the device further comprises a pump configured to providefluid to a distal portion of the elongate flexible drive shaft.

In some embodiments, a method for performing rotational atherectomy toremove stenotic lesion material from a blood vessel of a patient,includes: delivering a rotational atherectomy device into the bloodvessel. The rotational atherectomy device comprises: an elongateflexible drive shaft; an abrasive element coupled to a distal portion ofthe elongate flexible drive shaft; and a handle comprising an outerhousing. The handle further comprises: an electric motor coupled to aproximal portion of the elongate flexible drive shaft, the electricmotor configured to cause rotation of the elongate flexible drive shaftin a first rotational direction; and a pump configured to provide fluidto a distal portion of the elongate flexible drive shaft, wherein theouter housing contains the electric motor and the pump. The methodfurther includes rotating the drive shaft about the longitudinal axis inthe first rotational direction.

In some embodiments, a method for performing rotational atherectomy toremove stenotic lesion material from a blood vessel of a patient,includes: delivering a rotational atherectomy device into the bloodvessel, and rotating the drive shaft about the longitudinal axis in thefirst rotational direction. The rotational atherectomy device comprises:an elongate flexible drive shaft defining a longitudinal axis andcomprising a torque-transmitting coil; an abrasive element coupled to adistal portion of the elongate flexible drive shaft; and a handle,comprising: an electric motor coupled to a proximal portion of theelongate flexible drive shaft, the electric motor configured to causerotation of the elongate flexible drive shaft in a first rotationaldirection, such that rotation of the elongate flexible drive shaft inthe first rotational direction causes unwinding of the elongate flexibledrive shaft; and a control system configured to control rotation of theelectric motor.

In some embodiments, the torque-transmitting coil comprising one or morefilars that are helically wound around the longitudinal axis in a secondrotational direction. In some embodiments, the method further comprises:monitoring an amount of current supplied to the electric motor; andlimiting the amount of current supplied such that the amount of thecurrent does not exceed a threshold current value. In some embodiments,the method further comprises initiating a stopping protocol when theamount of the current supplied reaches a threshold current value. Insome embodiments, the stopping protocol comprises at least one ofreducing the amount of current supplied to the electric motor toapproximately zero or reversing rotation of the elongate drive shaftfrom the first rotational direction to a second rotational direction.

In some embodiments, a rotational atherectomy device for removingstenotic lesion material from a blood vessel of a patient, includes: anelongate flexible drive shaft defining a longitudinal axis andcomprising a torque-transmitting coil; an abrasive element coupled to adistal portion of the elongate flexible drive shaft; and a handle. Thehandle comprises: an electric motor coupled to a proximal portion of theelongate flexible drive shaft, the electric motor configured to causerotation of the elongate flexible drive shaft in a first rotationaldirection, such that rotation of the elongate flexible drive shaft inthe first rotational direction causes unwinding of the elongate flexibledrive shaft; and a control system configured to control rotation of theelectric motor by exclusively monitoring an amount of current suppliedto the electric motor and limiting the amount of current supplied suchthat the amount of the current does not exceed a threshold currentvalue.

In some embodiments, the threshold current value is configured to limitrotation of the elongate flexible drive shaft in the first rotationaldirection such that there is no unwinding of the one or more filars ofthe elongate flexible drive shaft. In some embodiments, the thresholdcurrent value is configured to limit rotation of the elongate flexibledrive shaft in the first rotational direction such that there is nochange in a maximum diameter of the elongate flexible drive shaft.

In some embodiments, a rotational atherectomy device for removingstenotic lesion material from a blood vessel of a patient, includes: anelongate flexible drive shaft; an abrasive element coupled to a distalportion of the elongate flexible drive shaft; and a handle comprising anouter housing. The handle further comprises: an electric motorcomprising a cannula configured to receive the elongate flexible driveshaft, wherein the electric motor is coupled to a proximal portion ofthe elongate flexible drive shaft and configured to rotate the elongateflexible drive shaft in a first rotational direction.

Some of the embodiments described herein may provide one or more of thefollowing advantages. First, some embodiments of the rotationalatherectomy system are configured to advance the drive shaft and thehandle assembly over a guidewire, and to use an electric motor to drivethe rotation of the drive shaft while the guidewire remains within thedrive shaft. Accordingly, in some embodiments the handle assembliesprovided herein include features that allow the drive shaft to bepositioned over a guidewire. Thereafter, the guidewire can be detainedin relation to the handle so that the guidewire will not rotate whilethe drive shaft is being rotated.

Second, some embodiments of the rotational atherectomy system include adrive shaft constructed of one or more helically wound filars that arewound in the same direction that the drive shaft is rotated during use.Accordingly, the turns of the helically wound filars can tend toradially expand and separate from each other (or “open up”) duringrotational use. Such a scenario advantageously reduces frictional lossesbetween adjacent filar turns. Additionally, when a guidewire is disposedwithin the lumen defined by the helically wound filars during rotationaluse, the drive shaft will tend to loosen on the guidewire rather than totighten on it. Consequently, in some cases no use of lubricant betweenthe guidewire and the drive shaft is necessary. Moreover, since thedrive shaft will tend to loosen on the guidewire, less stress will beinduced on the guidewire during rotation of the drive shaft. Thus, thepotential for causing breaks of the guidewire is advantageously reduced.Further, since the drive shaft will tend to loosen on the guidewireduring use, a larger guidewire can be advantageously used in some cases.

Third, some embodiments of the rotational atherectomy devices andsystems provided herein include multiple abrasive elements that areoffset from each other around the drive shaft such that the centers ofmass of the abrasive elements define a path that spirals around acentral longitudinal axis of the drive shaft. In particular embodiments,the rotational atherectomy systems are used by rotating the drive shaftaround the longitudinal axis in a direction opposite of the spiral pathdefined by the centers of mass of the abrasive elements. Such anarrangement can advantageously provide a smoother running and morecontrollable atherectomy procedure as compared to systems that rotatethe drive shaft in the same direction as the spiral path defined by thecenters of mass of the abrasive elements.

Fourth, some embodiments of the rotational atherectomy devices andsystems provided herein include a handle assembly with an electric motorthat is used to drive rotations of the drive shaft. Such an electricmotor can be entirely or substantially entirely housed within the handleassembly of the rotational atherectomy devices. The electric motor canprovide the benefits of providing increased control and reliability overthe rotational movement of the shaft. Such benefits can improve therotational responsiveness of rotational actuation of the shaft and canreduce or eliminate unintentional or excessive rotational actuationduring an atherectomy procedure. Furthermore, the electric motor doesnot rely on pneumatic equipment, and therefore eliminates the burden ofproviding pneumatic power, such as a compressed gas (e.g., air,nitrogen, or the like) supply, during a medical procedure. Additionally,the handle assembly can incorporate or externally couple a controlsystem for monitoring and controlling the rotation of the electricmotor.

Fifth, certain embodiments of the handle assembly may integrate a pumpor micropump, such as a saline pump (with a pump motor), within thehousing. The pump can provide the benefit of delivering saline, or otherfluids, to a distal end of the rotational atherectomy device, providinglubrication, and/or preventing blood from back flowing through a sheathof the rotational atherectomy device outside of the body. The integratedpump can increase the versatility of the handle assembly by eliminatingthe need to obtain and connect an external pump to the handle assemblyduring a medical procedure.

Also, by integrating the electric motor and pump into the handleassembly, additional advantages can be realized. For example, the handleassembly and/or the entire rotational atherectomy system provided hereincan be sterilizable as well as disposable, thus reducing the risk ofcontamination and infection.

Sixth, the handle assembly can also house a battery, or couple to abattery. Such a device would not need external power to operate, makingthe rotational atherectomy device more readily available in remote areaswith limited power supplies, or provide the user with increasedconvenience of use. As such, a clinician can have increased mobilitywith the handle assembly, as the handle assembly only needs to attach toan external fluid reservoir. Accordingly, a clinician would be lessrestricted and obstructed by connection cables during use.

Seventh, in some embodiments rotational atherectomy systems describedherein include user controls that are convenient and easy to operate. Inone such example, the user controls can include selectable elements onthe handle assembly, reducing the need for a clinician to operate asecondary control device while operating the handle assembly. Forexample, the user controls can include selectable elements thatcorrespond to the speed of drive shaft rotations. In some such examples,the user can conveniently select “low” or “high” speeds. Hence, in sucha case the clinician-user conveniently does not need to explicitlyselect or control the rpm of the drive shaft.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an example rotational atherectomy systemin accordance with some embodiments.

FIG. 2 is a top view of a handle assembly of the rotational atherectomysystem of FIG. 1 in accordance with some embodiments.

FIG. 3 is a perspective view of the handle assembly of FIG. 2 inaccordance with some embodiments.

FIG. 4 is an exploded view of the handle assembly of FIG. 2 inaccordance with some embodiments.

FIGS. 5, 6, and 7A-7B are perspective views of an interior of the handleassembly of FIG. 2 in accordance with some embodiments.

FIG. 8 is a schematic diagram representing an example drive shaftembodiment that includes filars that are wound in a direction oppositeto a direction of a spiral path defined by multiple abrasive elementsthat are arranged at differing radial angles in accordance with someembodiments.

FIG. 9 is a schematic diagram representing another example drive shaftembodiment that includes filars that are wound in a direction oppositeto the direction of a spiral path defined by multiple abrasive elementsthat are arranged at differing radial angles in accordance with someembodiments.

FIG. 10 is a longitudinal cross-sectional view of a distal portion of anexample rotational atherectomy device showing a multi-portion abrasiveelement and a distal stability element with an abrasive coating, inaccordance with some embodiments.

FIG. 11 is a side view of a distal portion of another example rotationalatherectomy device showing a multi-portion abrasive element and a distalstability element with an abrasive coating, with an unwinding of thedrive shaft (note that the figure shows unwinding in an exaggerated formfor instructive purposes), in accordance with some embodiments.

FIG. 12 shows the example rotational atherectomy device of FIG. 10 or 11in use at a first longitudinal position in the region of the lesion. Amulti-portion abrasive element of the rotational atherectomy device isbeing rotated along an orbital path to abrade the lesion.

FIG. 13 shows the rotational atherectomy device of FIG. 10 or 11 withthe abrasive element being rotated at a second longitudinal positionthat is distal of the first longitudinal position.

FIG. 14 shows the rotational atherectomy device of FIG. 10 or 11 withthe abrasive element being rotated at a third longitudinal position thatis distal of the second longitudinal position.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1 , in some embodiments a rotational atherectomysystem 100 for removing or reducing stenotic lesions in blood vesselscan include a guidewire 134, a handle assembly 200, and an elongateflexible drive shaft assembly 130. The drive shaft assembly 130 extendsdistally from the handle assembly 200. The handle assembly 200 can beoperated by a clinician to perform and control the rotationalatherectomy procedure.

In the depicted embodiment, the elongate flexible drive shaft assembly130 includes a sheath 132 and a flexible drive shaft 136. A proximal endof the sheath 132 is fixed to a distal end of the handle assembly 200.The flexible drive shaft 136 is slidably and rotatably disposed within alumen of the sheath 132. The flexible drive shaft 136 defines alongitudinal lumen in which the guidewire 134 is slidably disposed. Inthis embodiment, the flexible drive shaft 136 includes atorque-transmitting coil that defines the longitudinal lumen along acentral longitudinal axis, and the drive 136 shaft is configured torotate about the longitudinal axis while the sheath 132 remainsgenerally stationary. Hence, as described further below, during arotational atherectomy procedure the flexible drive shaft 136 is inmotion (e.g., rotating and longitudinally translating) while the sheath132 and the guidewire 134 are generally stationary.

In some optional embodiments, an inflatable member (not shown) cansurround a distal end portion of the sheath 132. Such an inflatablemember can be selectively expandable between a deflated low-profileconfiguration and an inflated deployed configuration. The sheath 132 maydefine an inflation lumen through which the inflation fluid can pass (toand from the optional inflatable member). The inflatable member can bein the deflated low-profile configuration during the navigation of thedrive shaft assembly 130 through the patient's vasculature to a targetlocation in a vessel. Then, at the target location, the inflatablemember can be inflated so that the outer diameter of the inflatablemember contacts the wall of the vessel. In that arrangement, theinflatable member advantageously stabilizes the drive shaft assembly 130in the vessel during the rotational atherectomy procedure.

Still referring to FIG. 1 , the flexible driveshaft 136 is slidably androtatably disposed within a lumen of the sheath 132. A distal endportion of the driveshaft 136 extends distally of the distal end of thesheath 132 such that the distal end portion of the driveshaft 136 isexposed (e.g., not within the sheath 132, at least not during theperformance of the actual rotational atherectomy).

In the depicted embodiment, the exposed distal end portion of thedriveshaft 136 includes one or more abrasive elements 138, a (optional)distal stability element 140, and a distal drive shaft extension portion142. In the depicted embodiment, the one or more abrasive elements 138are eccentrically-fixed to the driveshaft 136 proximal of the distalstability element 140. In this embodiment, the distal stability element140 is concentrically-fixed to the driveshaft 136 between the one ormore abrasive elements 138 and the distal drive shaft extension portion142. As such, the center of mass of the distal stability element 140 isaligned with the central axis of the drive shaft 136 while the center ofmass of each abrasive element 138 is offset from the central axis of thedrive shaft 136. The distal drive shaft extension portion 142, whichincludes the torque-transmitting coil, is configured to rotate about thelongitudinal axis extends distally from the distal stability element 140and terminates at a free end of the drive shaft 136.

In some optional embodiments, a proximal stability element (not shown)is included. The proximal stability element can be constructed andconfigured similarly to the depicted embodiment of the distal stabilityelement 140 (e.g., a metallic cylinder directly coupled to thetorque-transmitting coil of the drive shaft 136 and concentric with thelongitudinal axis of the drive shaft 136) while being located proximalto the one or more abrasive elements 138.

In the depicted embodiment, the distal stability element 140 has acenter of mass that is axially aligned with a central longitudinal axisof the drive shaft 136, while the one or more abrasive elements 138(collectively and/or individually) have a center of mass that is axiallyoffset from central longitudinal axis of the drive shaft 136.Accordingly, as the drive shaft 136 is rotated about its longitudinalaxis, the principle of centrifugal force will cause the one or moreabrasive elements 138 (and the portion of the drive shaft 136 to whichthe one or more abrasive elements 138 are affixed) to follow atransverse generally circular orbit (e.g., somewhat similar to a “jumprope” orbital movement) relative to the central axis of the drive shaft136. In general, faster speeds (rpm) of rotation of the drive shaft 136will result in larger diameters of the orbit (within the limits of thevessel diameter). The orbiting one or more abrasive elements 138 willcontact the stenotic lesion to ablate or abrade the lesion to a reducedsize (i.e., small particles of the lesion will be abraded from thelesion).

The rotating distal stability element 140 will remain generally at thelongitudinal axis of the drive shaft 136 as the drive shaft 136 isrotated. In some optional embodiments, two or more distal stabilityelements 140 are included. As described further below, contemporaneouswith the rotation of the drive shaft 136, the drive shaft 136 can betranslated back and forth along the longitudinal axis of the drive shaft136. Hence, lesions can be abraded radially and longitudinally by virtueof the orbital rotation and translation of the one or more abrasiveelements 138, respectively.

The flexible drive shaft 136 of rotational atherectomy system 100 islaterally flexible so that the drive shaft 136 can readily conform tothe non-linear vasculature of the patient, and so that a portion of thedrive shaft 136 at and adjacent to the one or more abrasive elements 138will laterally deflect when acted on by the centrifugal forces resultingfrom the rotation of the one or more eccentric abrasive elements 138. Inthis embodiment, the drive shaft 136 comprises one or more helicallywound wires (or filars) that provide one or more torque-transmittingcoils of the drive shaft 136 (as described below, for example, inconnection with FIGS. 8-11 ). In some embodiments, the one or morehelically wound wires are made of a metallic material such as, but notlimited to, stainless steel (e.g., 316, 316L, or 316LVM), nitinol,titanium, titanium alloys (e.g., titanium beta 3), carbon steel, oranother suitable metal or metal alloy. In some alternative embodiments,the filars are or include graphite, Kevlar, or a polymeric material. Insome embodiments, the filars can be woven, rather than wound. In someembodiments, individual filars can comprise multiple strands of materialthat are twisted, woven, or otherwise coupled together to form a filar.In some embodiments, the filars have different cross-sectionalgeometries (size or shape) at different portions along the axial lengthof the drive shaft 136. In some embodiments, the filars have across-sectional geometry other than a circle, e.g., an ovular, square,triangular, or another suitable shape.

In this embodiment, the drive shaft 136 has a hollow core. That is, thedrive shaft 136 defines a central longitudinal lumen runningtherethrough. The lumen can be used to slidably receive the guidewire134 therein, as will be described further below. In some embodiments,the lumen can be used to aspirate particulate or to convey fluids thatare beneficial for the atherectomy procedure.

In some embodiments, the drive shaft 136 includes an optional coating onone or more portions of the outer diameter of the drive shaft 136. Thecoating may also be described as a jacket, a sleeve, a covering, acasing, and the like. In some embodiments, the coating adds columnstrength to the drive shaft 136 to facilitate a greater ability to pushthe drive shaft 136 through stenotic lesions. In addition, the coatingcan enhance the rotational stability of the drive shaft 136 during use.In some embodiments, the coating is a flexible polymer coating thatsurrounds an outer diameter of the coil (but not the abrasive elements138 or the distal stability element 140) along at least a portion ofdrive shaft 136 (e.g., the distal portion of the drive shaft 136 exposedoutwardly from the sheath 132). In some embodiments, a portion of thedrive shaft 136 or all of the drive shaft 136 is uncoated. In particularembodiments, the coating is a fluid impermeable material such that thelumen of the drive shaft 136 provides a fluid impermeable flow pathalong at least the coated portions of the drive shaft 136.

The coating may be made of materials including, but not limited to,PEBEX, PICOFLEX, PTFE, ePTFE, FEP, PEEK, silicone, PVC, urethane,polyethylene, polypropylene, and the like, and combinations thereof. Insome embodiments, the coating covers the distal stability element 140and the distal extension portion 142, thereby leaving only the one ormore abrasive elements 138 exposed (non-coated) along the distal portionof the drive shaft 136. In alternative embodiments, the distal stabilityelement 140 is not covered with the coating, and thus would be exposedlike the abrasive element 140. In some embodiments, two or more layersof the coating can be included on portions of the drive shaft 136.Further, in some embodiments different coating materials (e.g., withdifferent durometers and/or stiffnesses) can be used at differentlocations on the drive shaft 136.

In the depicted embodiment, the distal stability element 140 is ametallic cylindrical member having an inner diameter that surrounds aportion of the outer diameter of the drive shaft 136. In someembodiments, the distal stability element 140 has a longitudinal lengththat is greater than a maximum exterior diameter of the distal stabilityelement 140. In the depicted embodiment, the distal stability element140 is coaxial with the longitudinal axis of the drive shaft 136.Therefore, the center of mass of the distal stability element 140 isaxially aligned (non-eccentric) with the longitudinal axis of the driveshaft 136. In alternative rotational atherectomy device embodiments,stability element(s) that have centers of mass that are eccentric inrelation to the longitudinal axis may be included in addition to, or asan alternative to, the coaxial stability elements 140. For example, insome alternative embodiments, the stability element(s) can have centersof mass that are eccentric in relation to the longitudinal axis and thatare offset 180 degrees (or otherwise oriented) in relation to the centerof mass of the one or more abrasive elements 138.

The distal stability element 140 may be made of a suitable biocompatiblematerial, such as a higher-density biocompatible material. For example,in some embodiments the distal stability element 140 may be made ofmetallic materials such as stainless steel, tungsten, molybdenum,iridium, cobalt, cadmium, and the like, and alloys thereof. The distalstability element 140 has a fixed outer diameter. That is, the distalstability element 140 is not an expandable member in the depictedembodiment. The distal stability element 140 may be mounted to thefilars of the drive shaft 136 using a biocompatible adhesive, bywelding, by press fitting, and the like, and by combinations thereof.The coating may also be used in some embodiments to attach or tosupplement the attachment of the distal stability element 140 to thefilars of the drive shaft 136. Alternatively, the distal stabilityelement 140 can be integrally formed as a unitary structure with thefilars of the drive shaft 136 (e.g., using filars of a different size ordensity, using filars that are double-wound to provide multiple filarlayers, or the like). The maximum outer diameter of the distal stabilityelement 140 may be smaller than the maximum outer diameters of the oneor more abrasive elements 138.

In some embodiments, the distal stability element 140 has an abrasivecoating on its exterior surface. For example, in some embodiments adiamond coating (or other suitable type of abrasive coating) is disposedon the outer surface of the distal stability element 140. In some cases,such an abrasive surface on the distal stability element 140 can helpfacilitate the passage of the distal stability element 140 throughvessel restrictions (such as calcified areas of a blood vessel).

In some embodiments, the distal stability element 140 has an exteriorcylindrical surface that is smoother and different from an abrasiveexterior surface of the one or more abrasive elements 138. That may bethe case whether or not the distal stability element 140 have anabrasive coating on its exterior surface. In some embodiments, theabrasive coating on the exterior surface of the distal stability element140 is rougher than the abrasive surfaces on the one or more abrasiveelements 138.

Still referring to FIG. 1 , the one or more abrasive elements 138 (whichmay also be referred to as a burr, multiple burrs, or (optionally) ahelical array of burrs) can comprise a biocompatible material that iscoated with an abrasive media such as diamond grit, diamond particles,silicon carbide, and the like. In the depicted embodiment, the abrasiveelements 138 includes a total of five discrete abrasive elements thatare spaced apart from each other. In some embodiments, one, two, three,four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen,fourteen, fifteen, or more than fifteen discrete abrasive elements areincluded as the one or more abrasive elements 138. Each of the fivediscrete abrasive elements can include the abrasive media coating, suchas a diamond grit coating.

In the depicted embodiment, the two outermost abrasive elements aresmaller in maximum diameter than the three inner abrasive elements. Insome embodiments, all of the abrasive elements are the same size. Inparticular embodiments, three or more different sizes of abrasiveelements are included. Any and all such possible arrangements of sizesof abrasive elements are envisioned and within the scope of thisdisclosure.

Also, in the depicted embodiment, the center of mass of each abrasiveelement 138 is offset from the longitudinal axis of the drive shaft 136.Therefore, as the eccentric one or more abrasive elements 138 arerotated (along an orbital path), at least a portion of the abrasivesurface of the one or more abrasive elements 138 can make contact withsurrounding stenotic lesion material. As with the distal stabilityelement 140, the eccentric one or more abrasive elements 138 may bemounted to the filars of the torque-transmitting coil of the drive shaft136 using a biocompatible adhesive, high temperature solder, welding,press fitting, and the like. In some embodiments, a hypotube is crimpedonto the driveshaft and an abrasive element is laser welded to thehypotube. Alternatively, the one or more abrasive elements 138 can beintegrally formed as a unitary structure with the filars of the driveshaft 136 (e.g., using filars that are wound in a different pattern tocreate an axially offset structure, or the like).

In some embodiments, the spacing of the distal stability element 140relative to the one or more abrasive elements 138 and the length of thedistal extension portion 142 can be selected to advantageously provide astable and predictable rotary motion profile during high-speed rotationof the drive shaft 136. For example, in embodiments that include thedistal driveshaft extension portion 142, the ratio of the length of thedistal driveshaft extension 142 to the distance between the centers ofthe one or more abrasive elements 138 and the distal stability element140 is about 1:0.5, about 1:0.8, about 1:1, about 1.1:1, about 1.2:1,about 1.5:1, about 2:1, about 2.5:1, about 3:1, or higher than 3:1.

Still referring to FIG. 1 , and further referring to FIGS. 2 and 3 , therotational atherectomy system 100 also includes the handle assembly 200.The handle assembly 200 includes a housing 202 and a carriage assembly204. The carriage assembly 204 is slidably translatable along thelongitudinal axis of the handle assembly 200 along an aperture 205defining a path, such that carriage assembly 204 along the longitudinalaxis as indicated by the arrow 115. For example, in some embodiments thecarriage assembly 204 can be translated, without limitation, about 8 cmto about 12 cm, or about 6 cm to about 10 cm, or about 4 cm to about 8cm, or about 6 cm to about 14 cm. As the carriage assembly 204 istranslated in relation to the housing 202, the drive shaft 136translates in relation to the sheath 132 in a corresponding manner.

In the depicted embodiment, the carriage assembly 204 includes anelectrical motor switch 206. While the electrical motor switch 206 isdepressed, power is supplied to the electric motor (as shown in FIGS.4-6, and 7A-7B) which is fixedly coupled to the drive shaft 136. Hence,an activation of the electrical motor switch 206 will result in arotation of the turbine member and, in turn, the drive shaft 136 (asdepicted by arrow 137). It should be understood that the rotationalatherectomy system 100 is configured to rotate the drive shaft 136 at ahigh speed of rotation (e.g., 20,000-160,000 rpm) such that theeccentric one or more abrasive elements 138 revolve in an orbital pathto thereby contact and remove portions of a target lesion (even thoseportions of the lesion that are spaced farther from the axis of thedrive shaft 136 than the maximum radius of the one or more abrasiveelements 138).

To operate the handle assembly 200 during a rotational atherectomyprocedure, a clinician can grasp the carriage assembly 204 and depressthe electrical motor switch 206 with the same hand. The clinician canmove (translate) the carriage assembly 204 distally and proximally byhand (e.g., back and forth in relation to the housing 202), whilemaintaining the electrical motor switch 206 in the depressed state. Inthat manner, a target lesion(s) can be ablated radially andlongitudinally by virtue of the resulting orbital rotation andtranslation of the one or more abrasive elements 138, respectively.

To further operate the handle assembly 200 during a rotationalatherectomy procedure, a clinician can select a rotational speed usingelectrical switches 210 a and 210 b. In some cases, the rotational speedcan be selected through a range of speeds with electrical switch 210 acausing an increase in speed and electrical switch 210 b causing adecrease in speed. In some embodiments, rotational speed is changedincrementally between a plurality of preset speeds. For example, asingle depression of electrical switch 210 a or 210 b will cause anincremental change in speed. In some embodiments, depression of theelectrical switch 210 a or 210 b will cause a change in speedcorresponding to a length of time that the electrical switch 210 a or210 b is depressed. In another embodiment, the electrical switch 210 awill cause a selection of a “high” rotational speed and the electricalswitch 210 b will cause a selection of a “low” rotational speed, incomparison to the high rotational speed.

Optionally, the electrical switches 210 a and 210 b can also include alight indicator. For example, when the electrical switches 210 a and 210b allow for selection for a “high” and “low” speed, respectively, theelectrical switches 210 a and 210 b can each have a single light, suchthat when a speed is selected, the light corresponding to the selectedelectrical switch 210 a or 210 b is illuminated to inform a clinician ofthe selected speed. In some embodiments, the light can shine throughelectrical switches 210 a and 210 b. Alternatively, a light can bepositioned proximal electrical switch 210 a and 210 b. As anotherexample, when the electrical switches 210 a and 210 b allow modificationof a speed between a range of speeds, the light indicator can be a lightbar, such that a number of lights illuminated on the light barcorrespond to a selected speed.

Optionally, handle assembly 200 can include an electrical pump switch212. Electrical pump switch 212 can turn a saline pump on and off. Insome cases, a first depression of the electrical pump switch 212 willturn the saline pump on, while a second depression will turn the salinepump on. In some embodiments, the electrical pump switch 212 includes alight indicator, such that when the pump is on, a light is illuminatedto inform the clinician that the pump is on.

During an atherectomy treatment, in some cases the guidewire 134 is leftin position in relation to the drive shaft 136 generally as shown. Forexample, in some cases the portion of the guidewire 134 that isextending beyond the distal end of the drive shaft 136 (or extensionportion 142) is about 10 inches to about 12 inches (about 25 cm to about30 cm), about 6 inches to about 16 inches (about 15 cm to about 40 cm),or about 2 inches to about 20 inches (about 5 cm to about 50 cm). Insome cases, the guidewire 134 is pulled back to be within (while notextending distally from) the drive shaft 136 during an atherectomytreatment. The distal end of the guidewire 134 may be positionedanywhere within the drive shaft 136 during an atherectomy treatment. Insome cases, the guidewire 134 may be completely removed from within thedrive shaft during an atherectomy treatment. The extent to which theguidewire 134 is engaged with the drive shaft 136 during an atherectomytreatment may affect the size of the orbital path of the one or moreabrasive elements 138. Accordingly, the extent to which the guidewire134 is engaged with the drive shaft 136 may be situationally selected tobe well-suited for a particular patient anatomy, physician's preference,type of treatment being delivered, and other such factors.

In the depicted embodiment, the handle assembly 200 also includes aguidewire detention mechanism 208. The guidewire detention mechanism 208can be selectively actuated (e.g., rotated) to releasably clamp andmaintain the guidewire 134 in a stationary position relative to thehandle assembly 200 (and, in turn, stationary in relation to rotationsof the drive shaft 136 during an atherectomy treatment). While the driveshaft 136 and handle assembly 200 are being advanced over the guidewire134 to put the one or more abrasive elements 138 into a targetedposition within a patient's vessel, the guidewire detention mechanism208 will be unactuated so that the handle assembly 200 is free to slidein relation to the guidewire 134. Then, when the clinician is ready tobegin the atherectomy treatment, the guidewire detention mechanism 208can be actuated to releasably detain/lock the guidewire 134 in relationto the handle assembly 200. That way the guidewire 134 will not rotatewhile the drive shaft 136 is rotating, and the guidewire 134 will nottranslate while the carriage assembly 204 is being manually translated.

In some embodiments, when the guidewire detention mechanism 208 isactuated to detain/lock the guidewire 134, a light indicator 214 canilluminate, such that a clinician can confirm the guidewire detentionmechanism 208 is actuated.

Optionally, the handle assembly 200 can include a safety mechanismregarding operation of the handle assembly. For example, rotation of thedrive shaft assembly 130 may be prohibited until the guidewire detentionmechanism 208 is actuated, the pump has been turned on via electricalpump switch 212, and a rotation speed has been selected via electricalswitch 210 a or 210 b. As another example, the indicator lightsassociated with the electrical switch 210 a or 210 b, the electricalpump switch 212, and the guidewire detention mechanism 208 lightindicator 214 will alert a clinician that the rotational atherectomysystem 100 should not be operated until all three systems (the motor,the pump, the guidewire lock) are lit. For example, each system may havea green light, such that three green lights indicates the clinician canproceed with the atherectomy procedure. Optionally, only the guidewiredetection mechanism 208 needs to be actuated to allow rotation of therotational atherectomy system 100.

Referring to FIGS. 4-6, and 7A-7B, an interior cavity 201 of the handleassembly 200 is shown. The housing 202 can include an upper housing 202a and a lower housing 202 b that encapsulate a motor assembly 220, apump assembly 230, and a controller assembly 240. The interior cavity201 can also house the electrical switches 210 a and 210 b, theelectrical pump switch 212, and the light indicator 214, collectively,user controls 216. In some cases, the user controls 216 can protrudethrough apertures of upper housing 202 a. In some embodiments, the usercontrols 216 can abut a flexible portion of upper housing 202 a, suchthat the user controls 216 can be actuated without direct contact. Insome embodiments, the handle assembly 200 is disposable. In someembodiments, the handle assembly 200 is a sterilized handle assembly, oris partially or fully sterilizable handle assembly. For example, in someembodiments, the handle can be sterilized using ethylene oxide (EtO)sterilization, or hydrogen peroxide sterilization.

The motor assembly 220 can include a motor 222 and, optionally, a gearassembly 224 (as shown in FIG. 7A). The motor 222 can be electric motor,such as a DC motor. Exemplary motors can include a brush DC motor, or abrushless DC motor. Other suitable motors may, however, include a servomotor, a stepper motor, and/or an AC motor. Motor 222 can bemechanically coupled to carriage assembly 204, such that motor 222 cantranslate along housing 202, and more specifically, inside sheath 132 tocause translation of drive shaft 136. Further, motor 222 can beelectrically coupled to electrical motor switch 206, such thatdepression of electrical motor switch 206 causes motor 222 to run. Insome embodiments, motor 222 can be directly coupled to drive shaft 136to cause rotation of drive shaft 136, and accordingly, abrasive elements138. For example, the motor 222 can include a cannulation through alongitudinal axis of the motor 222 that is configured to receive andsecure the drive shaft 136, direct drive of the drive shaft 136.

As mentioned above, motor assembly 220 can include a gear assembly 224.In some embodiments, the gear assembly 224 can have a 2:1 gear ratio toincrease an rpm output from motor 222. In some cases, using a motor withlower rpm capabilities, but supplementing the motor 222 with the gearassembly 224 can be more cost effective, especially for a disposablehandle assembly 200. For example, motor 222 can have an output of 40 krpm, and can cause rotation of the drive shaft 136 at 80 k rpm. Motor222 can be controlled by controller assembly 240, as will be describedbelow.

In another embodiment, as shown in FIG. 7B, motor assembly 220 caninclude a cannulated motor 226. Cannulated motor 226 can include acannulation to receive a hypotube of the rotational atherectomy device.In some embodiments, the cannulated motor 226 can provide a simplerdesign, which can reduce breakage by reducing the number of componentsinvolved in rotation of the elongate flexible drive shaft. Further,direct translation of the rotational components can increase simplicityof the design and operation of the rotational atherectomy device.Cannulated motor 226 can provide the improved torque transmission duringthe rotation of the elongate flexible drive shaft.

The pump assembly 230 can include a pump 232 (or micropump), tubes 234,an external fitting 236, and a pump motor 238. Pump 232 can pump saline,or other fluids, to a distal portion of rotational atherectomy device100. Pump 232 can be a peristaltic pump, a piezoelectric pump, anelectromechanical integrated pump, a microdosing pump, a positivedisplacement pump, a quasi-peristaltic pump, or other micropump. Pump232 can include one or more tubes 234 extend from, or extending through,pump 232 to pump saline from an exterior of housing 202 to a distal endof the rotational atherectomy device 100. In some embodiments, due tosterilization needs, it can be beneficial to use a pump with separationbetween the fluid and pump 232, such that the fluid only contacts tubes234. External fitting 236 can couple to tube 234 and further couple to atube external to housing 202. For example, external fitting 236 can be aluer fitting to couple a fluid bag (e.g., a saline bag). Pump 232 can bepowered by pump motor 238, which can be controlled by controllerassembly 240. Optionally, pump motor 238 can be a brushless DC motor.Pump motor 238 can allow pump 232 to operate at about 3.5 psi to about 4psi, such that the fluid pumped by pump 232 prevents backflow of bloodduring the atherectomy procedure. Pump assembly 230 can include seals toprevent leakage into housing 202.

The controller assembly 240 can include a housing 242, and a controller244. Housing 242 can provide a seal and barrier between controller 244and the other components of handle assembly 200 to protect thecontroller 244 from liquid (e.g., blood from a patient, fluid from thepump 232). In some embodiments, the housing 242 can also provide astructural support for the pump assembly 230, as shown in FIGS. 5-7 .The controller 244 can be electrically coupled to the components of theuser controls 216 and control function of the components.

For example, the controller 244 can cause motor 222 to run or stop basedon electrical motor switch 206, such that when electrical motor switch206 is depressed, controller 244 causes motor 222 to run. In addition,controller 244 can determine and control a speed for rotating the driveshaft 136, and supply the appropriate power to the motor 222 based onuser input via electrical switches 210 a and/or 210 b. For example, therotational speed can be selected through a range of speeds withelectrical switch 210 a causing an increase in speed and electricalswitch 210 b causing a decrease in speed. In some embodiments,rotational speed is changed incrementally between a plurality of presetspeeds. As such, a single depression of electrical switch 210 a or 210 bcan cause controller 244 to increase current supplied to the motor 222to cause an incremental change in speed. In some embodiments, depressionof the electrical switch 210 a or 210 b will cause controller 244 tosupply a current to cause a change in speed corresponding to a length oftime that the electrical switch 210 a or 210 b is depressed. In anotherembodiment, the electrical switch 210 a will cause controller 244 todetermine a selection of a “high” rotational speed was made and providethe appropriate current, and the electrical switch 210 b will causecontroller 244 to determine a selection of a “low” rotational speed, incomparison to the high rotational speed, was made and provide theappropriate current. Additionally, controller 244 can control the lightindicators associated with electrical switches 210 a and 210 b, asdescribed above.

In some embodiments, the controller 244 can monitor and control aparameter, such as an amount of current supplied to the motor 222. Suchmonitoring and controlling features can provide a safety (shut-off)feature to the rotational atherectomy system 100 that prevents damagefrom occurring to the system 100 and/or a patient during use. Forexample, in various embodiments, the controller 244 is configured suchthat the current supplied does not exceed a threshold current value(e.g., prevents a large amount of current from being supplied to motor222). Thus, the controller 244 can be programmed to provide current tothe motor 222, but at a current level that is no greater than thethreshold current value. The controller 244 can optionally limit thesystem 100 based exclusively on the current threshold value, in someembodiments, to provide an effective, yet simplified algorithm to thecontroller 244 as a safety feature.

The threshold current value can be a predetermined value that preventsirreversible damage or undesirable performance of the system 100 fromoccurring during use. For example, in some embodiments, the thresholdcurrent value is configured to limit the torque and/or speed of rotationof the system 100 such that the rotation of the elongate flexible driveshaft in a particular rotational direction (e.g., a first rotationaldirection) does not cause unwinding of the one or more filars of theelongate flexible drive shaft to occur. In some embodiments, thethreshold current value is configured to limit the torque and/or speedof rotation of the system 100 such that the rotation of the elongateflexible drive shaft in a particular rotational direction (e.g., a firstrotational direction) does not cause a change in a maximum diameter ofthe elongate flexible drive shaft to occur.

In some embodiments, if the current supplied reaches a threshold currentvalue, the controller 244 can initiate a stopping protocol. For example,the stopping protocol can cause the controller 244 to reduce the amountof current supplied to the electrical motor to approximately zero. Insome embodiments, such a reduction of current supplied can occur in ashort period of time, substantially instantaneously, or over a longerperiod of time. In some embodiments, the stopping protocol can cause thecontroller 244 to reverse the direction of rotation of the motor 222,and therefore the rotation of the drive shaft 136. Such a reversal indirection of rotation of the drive shaft 136 can cause rotation of adistal end of the drive shaft to 136 to slow down or stop. The stoppingprotocol can aid in preventing motor 222 from burning out. In somecases, the stopping protocol is caused to a distal portion of driveshaft 136 being stuck in a vessel. Optionally, once rotation has begun,the stopping protocol can be executed after a predetermined amount oftime (e.g., about 0.1 seconds to about 60 seconds). In some cases, thepredetermined amount of time for executing the stopping protocol can beselected such that the predetermined amount of time begins when thecurrent threshold is reached. For example, the drive shaft coil maybegin to unwind once the current threshold is reached, and thecontroller may continue to provide current to the motor until thepredetermined amount of time has passed. In some cases, the drive shaftcoil may begin to unwind before the current threshold is reached, andthe controller will continue to motor the current supplied and initiatethe stopping protocol after the current threshold is reached.

Optionally, controller 244 can cause pump motor 238 to run or stop pump232 based on depression of electrical pump switch 212. In some cases, afirst depression of the electrical pump switch 212 will turn the salinepump on, while a second depression will turn the saline pump on. In someembodiments, the controller 244 control the light indicator associatedwith electrical pump switch 212, such that when the pump is on, a lightis illuminated to inform the clinician that the pump is on.

In some embodiments, controller 244 can monitor guidewire detentionmechanism 208 (e.g., via a sensor), such that controller 244 candetermine when guidewire detention mechanism 208 is actuated (e.g.,rotated) to releasably clamp and maintain the guidewire 134 in astationary position relative to the handle assembly 200 (and, in turn,stationary in relation to rotations of the drive shaft 136 during anatherectomy treatment). In some embodiments, when the clinician is readyto begin the atherectomy treatment, the guidewire detention mechanism208 can be actuated to releasably detain/lock the guidewire 134 inrelation to the handle assembly 200. That way the guidewire 134 will notrotate while the drive shaft 136 is rotating, and the guidewire 134 willnot translate while the carriage assembly 204 is being manuallytranslated. Accordingly, controller 244 can prevent motor 222 fromrotating the drive shaft 136 unless controller 244 detects that theguidewire detention mechanism 208 is actuated. Further, controller 244can control illumination of the light indicator 214.

Optionally, the controller 244 can include a safety mechanism regardingoperation of the handle assembly 200. For example, rotation of the driveshaft assembly 130 may be prohibited until the controller 244 detectsthat guidewire detention mechanism 208 is actuated, the pump has beenturned on via electrical pump switch 212, and a rotation speed has beenselected via electrical switch 210 a or 210 b. As another example, thecontroller 244 can selectively illuminate indicator lights associatedwith the electrical switch 210 a or 210 b, the electrical pump switch212, and the guidewire detention mechanism 208 light indicator 214 toinform a clinician which systems are powered on. In some embodiments, alack of three lights indicts to the clinician that the rotationalatherectomy system 100 should not be operated, at least until all threesystems (the motor, the pump, the guidewire lock) are lit. For example,each system may have a green light, such that three green lightsindicates the clinician can proceed with the atherectomy procedure.Optionally, only the guidewire detection mechanism 208 needs to beactuated for the controller 244 to allow rotation of the rotationalatherectomy system 100.

In some embodiments, the handle assembly 200 can also include a batteryor other power source (not shown). The battery or power source may beintegrated into the housing 202. For example, the battery could bedisposable with handle assembly 200. In some embodiments, the powersource could have an external component configured to make an electricalconnection (e.g., plug into a wall socket) to provide power. Optionally,the battery could be reusable. For example, housing 202 can beconfigured to receive a rechargeable battery, either on an exteriorportion of housing 202, or within interior cavity 201.

Referring to FIG. 8 , a schematic diagram 150 a depicting an end view ofthe drive shaft 136 (looking distally) with the abrasive elements 138can be used to illustrate the filar spiral wind direction 131 a (of thedrive shaft 136) in comparison to the spiral path defined by theabrasive element centers of mass 133 a (of the abrasive elements 138 ofFIG. 10 , and the abrasive elements 144 a-e of FIG. 11 ), and also incomparison to the rotation direction 145 a of the drive shaft 136 duringuse. In the depicted embodiment, the filar spiral wind direction 131 ais clockwise around the central longitudinal axis 135 of the drive shaft136. Also, the rotation direction 145 a of the drive shaft 136 duringuse is clockwise around the central longitudinal axis 135 of the driveshaft 136. In contrast, the spiral path defined by the abrasive elementcenters of mass 133 a is counterclockwise around the centrallongitudinal axis 135 of the drive shaft 136. In other words, the filarspiral wind direction 131 a and the rotation direction 145 a of thedrive shaft 136 during use are the same direction, whereas the spiralpath defined by the abrasive element centers of mass 133 a is theopposite direction of: (i) the filar spiral wind direction 131 a and(ii) the opposite direction of the rotation direction 145 a of the driveshaft 136 during use.

Referring also to FIG. 9 , another schematic diagram 150 b depicting anend view of the drive shaft 136 (looking distally) with the abrasiveelements 144 a-e (as shown in FIG. 11 ) can be used to illustrateanother arrangement of the filar spiral wind direction 131 b (of thedrive shaft 136) in comparison to the spiral path defined by theabrasive element centers of mass 133 b (of the abrasive elements 144a-e), and also in comparison to the rotation direction 145 b of thedrive shaft 136 during use. In the depicted embodiment, the filar spiralwind direction 131 b is counterclockwise around the central longitudinalaxis 135 of the drive shaft 136. Also, the rotation direction 145 b ofthe drive shaft 136 during use is counterclockwise around the centrallongitudinal axis 135 of the drive shaft 136. In contrast, the spiralpath defined by the abrasive element centers of mass 133 b is clockwisearound the central longitudinal axis 135 of the drive shaft 136. Inother words, here again in this example, the filar spiral wind direction131 b and the rotation direction 145 b of the drive shaft 136 during useare the same direction, whereas the spiral path defined by the abrasiveelement centers of mass 133 b is the opposite direction of: (i) thefilar spiral wind direction 131 b and (ii) the opposite direction of therotation direction 145 b of the drive shaft 136 during use.

The relative arrangements between: (i) the filar spiral wind direction131 a or 131 b, (ii) the spiral path defined by the abrasive elementcenters of mass 133 a or 133 b, and (iii) the rotation direction 145 aor 145 b of the drive shaft 136 during use, as described above inreference to FIGS. 9 and 10 , provide particular operational advantagesin some usage scenarios. For example, when the direction of rotation andthe direction the filars are wound are the same direction, the winds ofthe filars will tend to radially expand (the drive shaft 136 will tendto “open up,” as shown in FIGS. 10 and 11 ), resulting in less friction,little to no need for lubrication, less stress induced on the guidewire,and so on. Additionally, when the direction of rotation of the driveshaft 136 and the direction of the spiral path defined by the centers ofmass of the abrasive elements 144 are opposite, such an arrangement canadvantageously provide a smoother running and more controllableatherectomy procedure as compared to systems that rotate the drive shaftin the same direction as the spiral path defined by the centers of massof the abrasive elements. For example, rather than causing the abrasiveelements 144 to corkscrew into the stenotic lesion material (as canoccur when the drive shaft rotational direction is the same as thedirection of the spiral path defined by the centers of mass of theabrasive elements), the abrasive elements 144 can instead abrade thestenotic lesion material in more of a gradual, smooth, and controllablemanner.

Referring to FIG. 10 , a distal end portion of the drive shaft 136 isshown in a longitudinal cross-sectional view. The distal end portion ofthe drive shaft 136 includes the one or more abrasive elements 138 thatare eccentrically-fixed to the driveshaft 136, the optional distalstability element 140 with an abrasive outer surface, and the distaldrive shaft extension portion 142.

In the depicted embodiment, the one or more abrasive elements 138includes a total of five discrete abrasive elements that are spacedapart from each other. In some embodiments, one, two, three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, or more than fifteen discrete abrasive elements are included asthe one or more abrasive elements 138. Each of the five discreteabrasive elements can include the abrasive media coating.

In the depicted embodiment, the two outermost abrasive elements of theabrasive elements 138 are smaller in maximum diameter than the threeinner abrasive elements of the abrasive elements 138. In someembodiments, all of the abrasive elements are the same size. Inparticular embodiments, three or more different sizes of abrasiveelements are included. Any and all such possible arrangements of sizesof abrasive elements are envisioned and within the scope of thisdisclosure.

The one or more abrasive elements 138 can be made to any suitable size.For clarity, the size of the one or more abrasive elements 138 willrefer herein to the maximum outer diameter of individual abrasiveelements of the one or more abrasive elements 138. In some embodiments,the one or more abrasive elements 138 are about 2 mm in size (maximumouter diameter). In some embodiments, the size of the one or moreabrasive elements 138 is in a range of about 1.5 mm to about 2.5 mm, orabout 1.0 mm to about 3.0 mm, or about 0.5 mm to about 4.0 mm, withoutlimitation. Again, in a single embodiment, one or more of the abrasiveelements 138 can have a different size in comparison to the otherabrasive elements 138. In some embodiments, the two outermost abrasiveelements are about 1.5 mm in diameter and the inner abrasive elementsare about 2.0 mm in diameter.

In the depicted embodiment, the one or more abrasive elements 138,individually, are oblong in shape. A variety of different shapes can beused for the one or more abrasive elements 138. For example, in someembodiments the one or more abrasive elements 138 are individuallyshaped as spheres, discs, rods, cylinders, polyhedrons, cubes, prisms,and the like. In some embodiments, such as the depicted embodiment, allof the one or more abrasive elements 138 are the same shape. Inparticular embodiments, one or more of the abrasive elements 138 has adifferent shape than one or more of the other abrasive elements 138.That is, two, three, or more differing shapes of individual abrasiveelements 138 can be combined on the same drive shaft 136.

In the depicted embodiment, adjacent abrasive elements of the one ormore abrasive elements 138 are spaced apart from each other. Forexample, in the depicted embodiment the two distal-most individualabrasive elements are spaced apart from each other by a distance ‘X’. Insome embodiments, the spacing between adjacent abrasive elements isconsistent between all of the one or more abrasive elements 138.Alternatively, in some embodiments the spacing between some adjacentpairs of abrasive elements differs from the spacing between otheradjacent pairs of abrasive elements.

In some embodiments, the spacing distance X in ratio to the maximumdiameter of the abrasive elements 138 is about 1:1. That is, the spacingdistance X is about equal to the maximum diameter. The spacing distanceX can be selected to provide a desired degree of flexibility of theportion of the drive shaft 136 to which the one or more abrasiveelements 138 are attached. In some embodiments, the ratio is about 1.5:1(i.e., X is about 1.5 times longer than the maximum diameter). In someembodiments, the ratio is in a range of about 0.2:1 to about 0.4:1, orabout 0.4:1 to about 0.6:1, or about 0.6:1 to about 0.8:1, or about0.8:1 to about 1:1, or about 1:1 to about 1.2:1, or about 1.2:1 to about1.4:1, or about 1.4:1 to about 1.6:1, or about 1.6:1 to about 1.8:1, orabout 1.8:1 to about 2.0:1, or about 2.0:1 to about 2.2:1, or about2.2:1 to about 2.4:1, or about 2.4:1 to about 3.0:1, or about 3.0:1 toabout 4.0:1, and anywhere between or beyond those ranges.

In the depicted embodiment, the center of mass of each one of the one ormore abrasive elements 138 is offset from the longitudinal axis of thedrive shaft 136 along a same radial angle. Said another way, the centersof mass of all of the one or more abrasive elements 138 are coplanarwith the longitudinal axis of the drive shaft 136. If the size of eachof the one or more abrasive elements 138 is equal, the centers of massof the one or more abrasive elements 138 would be collinear on a linethat is parallel to the longitudinal axis of the drive shaft 136.

Referring to FIG. 11 , according to some embodiments of the rotationalatherectomy devices provided herein, one or more abrasive elements 144are arranged at differing radial angles in relation to the drive shaft136 as depicted here. Further, the draft shaft 136 is shown as in anunwinding state, as unwinding may optionally occur during rotation ofthe drive shaft 136 in some embodiments. In such a case, a path definedby the centers of mass of the one or more abrasive elements 144 spiralsalong the drive shaft 136 around the central longitudinal axis of thedrive shaft 136. In some cases (e.g., when the diameters of the one ormore abrasive elements 144 are equal and the adjacent abrasive elementsare all equally spaced), the centers of mass of the one or more abrasiveelements 144 define a helical path along/around the drive shaft 136. Ithas been found that such arrangements can provide a desirably-shapedorbital rotation of the one or more abrasive elements 144. It should benoted that, in some embodiments, a controller assembly (e.g., controllerassembly 240) is configured to control rotation and current input suchthat the drive shaft 136 is prevented from unwinding during rotation ofthe drive shaft 136.

It should be understood that any of the structural features described inthe context of one embodiment of the rotational atherectomy devicesprovided herein can be combined with any of the structural featuresdescribed in the context of one or more other embodiments of therotational atherectomy devices provided herein. For example, the size,spacing, and/or shape features (and any other characteristics) of theone or more abrasive elements 138 described in the context of FIG. 1 canbe incorporated in any desired combination with the spiral arrangementof the one or more abrasive elements 144.

In some embodiments, the drive shaft assembly 130 includes at least fourabrasive elements 144 attached to a distal end portion of the driveshaft 136 and each has a center of mass offset from the longitudinalaxis of the drive shaft 136. A spiral path defined by connecting thecenters of mass of the at least four abrasive elements 144 spiralsaround the longitudinal axis of the drive shaft 136. An overall radialangle of the spiral path is defined by a radial angle between adistal-most abrasive element of the at least four abrasive elements 144and a proximal-most abrasive element of the at least four abrasiveelements 144. In some embodiments, the overall radial angle of thespiral path of the at least four abrasive elements 144 is always lessthan 180 degrees along any 10 cm length of the distal end portion of thedrive shaft 136. In some embodiments, the overall radial angle of thespiral path of the at least four abrasive elements 144 is always lessthan 170 degrees, or less than 160 degrees, or less than 150 degrees, orless than 140 degrees, or less than 130 degrees, or less than 120degrees, or less than 110 degrees, or less than 100 degrees, or lessthan 90 degrees along any 10 cm length of the distal end portion of thedrive shaft 136.

In some embodiments, such as the depicted embodiment, the drive shaftassembly 130 includes a concentric abrasive tip member 141. Theconcentric abrasive tip member 141 can be affixed to, and extendingdistally from, a distal-most end of the drive shaft 136. In someembodiments that include the concentric abrasive tip member 141, nodistal stability element is included 140. In particular embodiments(such as the depicted embodiment), the concentric abrasive tip member141 and the distal stability element are both included 140.

In some embodiments the concentric abrasive tip member 141 may be madeof metallic materials such as stainless steel, tungsten, molybdenum,iridium, cobalt, cadmium, and the like, and alloys thereof. Theconcentric abrasive tip member 141 has a fixed outer diameter. That is,the concentric abrasive tip member 141 is not an expandable member inthe depicted embodiment. The concentric abrasive tip member 141 may bemounted to the filars of the drive shaft 136 using a biocompatibleadhesive, by welding, by press fitting, and the like, and bycombinations thereof. Alternatively, the concentric abrasive tip member141 can be integrally formed as a unitary structure with the filars ofthe drive shaft 136 (e.g., using filars of a different size or density,using filars that are double-wound to provide multiple filar layers, orthe like).

In some embodiments, the concentric abrasive tip member 141 has anabrasive coating on its exterior surface. In particular embodiments, theconcentric abrasive tip member 141 includes an abrasive material alongan exterior circumferential surface, or on a distal end face/surface, orboth. For example, in some embodiments a diamond coating (or othersuitable type of abrasive coating) is disposed on the outer surface ofthe concentric abrasive tip member 141. In some cases, such an abrasivesurface on the concentric abrasive tip member 141 can help facilitatethe passage of the concentric abrasive tip member 141 through vesselrestrictions (such as calcified areas of a blood vessel).

In some embodiments, the concentric abrasive tip member 141 has anexterior surface that is smoother and different from an abrasiveexterior surface of the one or more abrasive elements 138. That may bethe case whether or not the concentric abrasive tip member 141 have anabrasive coating on its exterior surface. In some embodiments, theabrasive coating on the exterior surface of the concentric abrasive tipmember 141 is rougher than the abrasive surfaces on the one or moreabrasive elements 138.

The maximum outer diameter of the concentric abrasive tip member 141 maybe smaller than, equal to, or larger than the outer diameter of theadjacent portion of the drive shaft 136. The maximum outer diameter ofthe concentric abrasive tip member 141 may be smaller than, equal to, orlarger than the maximum outer diameter of each of the one or moreabrasive elements 144 a-e. The lateral width of the concentric abrasivetip member 141 (e.g., measured parallel to the longitudinal axis of thedrive shaft 136) may be smaller than, equal to, or larger than themaximum lateral width of each of the one or more abrasive elements 144a-e. The concentric abrasive tip member 141 defines a central openingthat is coaxial with the lumen defined by the drive shaft 136.Accordingly, a guidewire (e.g., the guidewire 134 of FIG. 1 ) can extendthrough the concentric abrasive tip member 141. In some embodiments, theconcentric abrasive tip member 141 is shaped as a toroid. In particularembodiments, the concentric abrasive tip member 141 is shaped as ahollow cylinder. In certain embodiments, the outer surface of theconcentric abrasive tip member 141 defines one or more grooves, teeth,edges, and the like, and combinations thereof.

Next, as depicted by FIGS. 12-14 , the rotation and translationalmotions of the drive shaft 136 (and the one or more abrasive elements138) can be commenced to perform ablation of the lesion 14.

In some implementations, prior to the ablation of the lesion 14 by theone or more abrasive elements 138, an inflatable member can be used asan angioplasty balloon to treat the lesion 14. That is, an inflatablemember (on the sheath 132, for example) can be positioned within thelesion 14 and then inflated to compress the lesion 14 against the innerwall 12 of the vessel 10. Thereafter, the rotational atherectomyprocedure can be performed. In some implementations, such an inflatablemember can be used as an angioplasty balloon after the rotationalatherectomy procedure is performed. In some implementations,additionally or alternatively, a stent can be placed at lesion 14 usingan inflatable member on the sheath 132 (or another balloon memberassociated with the drive shaft assembly 130) after the rotationalatherectomy procedure is performed.

The guidewire 134 may remain extending from the distal end of the driveshaft 136 during the atherectomy procedure as shown. For example, asdepicted by FIGS. 12-14 , the guidewire 134 extends through the lumen ofthe drive shaft 136 and further extends distally of the distal end ofthe distal extension portion 142 during the rotation and translationalmotions of the drive shaft 136 (refer, for example, to FIGS. 12-14 ). Insome alternative implementations, the guidewire 134 is withdrawncompletely out of the lumen of the drive shaft 136 prior to during therotation and translational motions of the drive shaft 136 for abradingthe lesion 14. In other implementations, the guidewire is withdrawn onlypartially. That is, in some implementations a portion of the guidewireremains within the lumen of the drive shaft 136 during rotation of thedrive shaft 136, but remains only in a proximal portion that is notsubject to the significant orbital path in the area of the one or moreabrasive elements 138 (e.g., remains within the portion of the driveshaft 136 that remains in the sheath 132).

To perform the atherectomy procedure, the drive shaft 136 is rotated ata high rate of rotation (e.g., 20,000-160,000 rpm) such that theeccentric one or more abrasive elements 138 revolve in an orbital pathabout an axis of rotation and thereby contacts and removes portions ofthe lesion 14.

Still referring to FIGS. 12-14 , the rotational atherectomy system 100is depicted during the high-speed rotation of the drive shaft 136. Thecentrifugal force acting on the eccentrically weighted one or moreabrasive elements 138 causes the one or more abrasive elements 138 toorbit in an orbital path 131 a around the axis of rotation 135. In someimplementations, the orbital path can be somewhat similar to the orbitalmotion of a “jump rope.” As shown, some portions of the drive shaft 136(e.g., a portion that is just distal of the sheath 132 and anotherportion that is distal of the distal stability element 140) can remainin general alignment with the axis of rotation 135, but the particularportion of the drive shaft 136 adjacent to the one or more abrasiveelements 138 is not aligned with the axis of rotation 135 (and insteadorbits around the axis 135). As such, in some implementations, the axisof rotation 135 may be aligned with the longitudinal axis of a proximalpart of the drive shaft 136 (e.g., a part within the distal end of thesheath 132) and with the longitudinal axis of the distal extensionportion 142 of the drive shaft 136.

In some implementations, as the one or more abrasive elements 138rotates, the clinician operator slowly advances the carriage assembly204 distally (and, optionally, reciprocates both distally andproximally) in a longitudinal translation direction so that the abrasivesurface of the one or more abrasive elements 138 scrapes againstadditional portions of the occluding lesion 14 to reduce the size of theocclusion, and to thereby improve the blood flow through the vessel 10.This combination of rotational and translational motion of the one ormore abrasive elements 138 is depicted by the sequence of FIGS. 12-14 .

In some embodiments, the sheath 132 may define one or more lumens (e.g.,the same lumen as, or another lumen than, the lumen in which the driveshaft 136 is located) that can be used for aspiration (e.g., of abradedparticles of the lesion 14). In some cases, such lumens can beadditionally or alternatively used to deliver perfusion and/ortherapeutic substances to the location of the lesion 14, or to preventbackflow of blood from vessel 10 into sheath 132.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, design features of the embodiments described herein can becombined with other design features of other embodiments describedherein. Accordingly, other embodiments are within the scope of thefollowing claims.

What is claimed is:
 1. A rotational atherectomy method, comprising:connecting luer fitting of a rotational atherectomy control handle to anexternal tube in fluid communication with a fluid supply comprisingsaline, wherein fluid supplied through the luer fitting of therotational atherectomy control handle is deliverable to a central lumenof a sheath connected to a front portion of an outer handle housing ofthe rotational atherectomy control handle via a pump housed within anouter handle housing that is selectively activated by a control assemblyhoused within the outer handle housing to deliver the fluid to thecentral lumen of the sheath while a torque-transmitting coil is disposedwithin the central lumen of the sheath; advancing thetorque-transmitting coil over a guidewire to a targeted blood vesselwhile the torque-transmitting coil is disposed within the central lumenof the sheath such that at least one eccentric abrasive element fixedlymounted to a distal end portion of the torque-transmitting coil ispositioned distally of a distal end of the sheath, wherein a rearguidewire port accessible along a rear portion of the outer handlehousing is configured to receive a proximal portion of the guidewirewhile a distal portion of the guidewire extends distally of thetorque-transmitting coil; and actuating an atherectomy trigger buttonmovably mounted relative to the outer handle housing and being incommunication with the controller assembly housed within the outerhandle housing so as to activate an electric motor housed within theouter handle housing to drive rotation of the torque-transmitting coilrelative to the sheath connected to the front portion of an outer handlehousing, wherein both the atherectomy trigger button and the electricmotor are carried by a carriage that is arranged within the outer handlehousing and that is movable relative to the outer handle housing so asto longitudinally translate the torque-transmitting coil within thecentral lumen of sheath, and wherein a user interface accessible alongan upper exterior face of the outer handle housing includes: theatherectomy trigger button, a plurality of rotation speed controlbuttons positioned rearward of the atherectomy trigger button for inputof a selected rotational speed setting for the torque-transmitting coil,and a fluid delivery button positioned rearward of the plurality ofrotation speed control buttons.
 2. The method of claim 1, furthercomprising actuating the fluid delivery button accessible along theupper exterior face of the outer handle housing to initiating deliveryof the fluid supplied through the luer fitting to the central lumen ofthe sheath.
 3. The method of claim 2, wherein the controller assemblyhoused within the outer handle housing is responsive said actuating thefluid delivery button so as to activate the pump housed within the outerhandle housing to drive fluid flow to the central lumen of the sheath.4. The method of claim 3, wherein the controller assembly housed withinthe outer handle housing is responsive to actuation of at least one ofthe rotation speed control buttons so as to regulate a rotational speedof the torque-transmitting coil by controlling the electric motor torotate the torque-transmitting coil according to the selected rotationalspeed setting.
 5. The method of claim 4, further comprising adjusting aguidewire brake actuator disposed along the rear portion of the outerhandle housing to releasably lock the guidewire when the guidewire ispositioned in the rear guidewire port accessible along the rear portionof the outer handle housing.
 6. The method of claim 5, the userinterface accessible along the upper exterior face of the outer handlehousing further includes: a guidewire brake light indicator positionedrearward of the fluid delivery button, wherein the controller assemblyhoused within the outer handle housing controls illumination of theguidewire brake light indicator in response to movement of the guidewirebrake actuator disposed along the rear portion of the outer handlehousing being moved to a locked position.
 7. The method of claim 1,wherein said activating the electric motor to drive rotation of thetorque-transmitting coil comprises rotating a set of gears housed withinthe outer handle housing and carried by the carriage, the set of gearsbeing coupled between the electric motor and the torque-transmittingcoil.
 8. The method of claim 1, wherein the torque-transmitting coil hasan exterior coil diameter defined by one or more filars helically woundin a filar wind direction, and wherein said activating the electricmotor to drive rotation of the torque-transmitting coil comprisesdriving rotation of the torque-transmitting coil in a first rotationaldirection that is the same as the filar wind direction.
 9. The method ofclaim 1, wherein the torque-transmitting coil terminates at a concentricmetallic tip mounted to a distal-most end of the torque-transmittingcoil, the concentric metallic tip having an annular body that extendsdistally from the torque-transmitting coil and an exterior tip diametersmaller than an exterior coil diameter of the torque-transmitting coil,wherein the concentric metallic tip has a central opening to receive theguidewire and has an exterior surface that is smoother than theeccentric abrasive element.
 10. The method of claim 1, wherein the atleast one eccentric abrasive element comprises a first eccentricabrasive element, further comprising at least a second eccentricabrasive element spaced distally apart from the first eccentric abrasiveelement along the torque-transmitting coil.
 11. A rotational atherectomymethod, comprising: securing a fluid connector of a rotationalatherectomy control handle to an external tube in fluid communicationwith a fluid supply comprising saline, wherein fluid supplied throughthe fluid connector is deliverable to a central lumen of a sheathconnected to a front portion of an outer handle housing of therotational atherectomy control handle via a pump housed within an outerhandle housing that is regulated by a control assembly housed within theouter handle housing to deliver the fluid to the central lumen of thesheath while a torque-transmitting coil is disposed within the centrallumen of the sheath; advancing the torque-transmitting coil over aguidewire to a targeted blood vessel while the torque-transmitting coilis disposed within the central lumen of the sheath such that at leastone eccentric abrasive element fixedly mounted to a distal end portionof the torque-transmitting coil is positioned distally of a distal endof the sheath; and actuating an atherectomy activation button movablymounted relative to the outer handle housing and being in communicationwith the controller assembly housed within the outer handle housing soas to activate an electric motor housed within the outer handle housingto drive rotation of the torque-transmitting coil and the at least oneeccentric abrasive element within the targeted blood vessel; wherein therotational atherectomy control handle includes a user interface that isaccessible along an upper exterior face of the outer handle housing andthat comprises the atherectomy activation button, a plurality ofrotation speed control buttons positioned rearward of the atherectomytrigger button for input of a selected rotational speed setting for thetorque-transmitting coil, and a fluid delivery button positionedrearward of the plurality of rotation speed control buttons.
 12. Themethod of claim 11, further comprising actuating the fluid deliverybutton accessible along the upper exterior face of the outer handlehousing to control delivery of the fluid supplied through the fluidconnector to the central lumen of the sheath, wherein the controllerassembly housed within the outer handle housing is responsive to saidactuating the fluid delivery button so as to activate the pump housedwithin the outer handle housing to drive fluid flow to the central lumenof the sheath.
 13. The method of claim 12, wherein the controllerassembly housed within the outer handle housing is responsive toactuation of at least one of the rotation speed control buttons so as toregulate a rotational speed of the torque-transmitting coil bycontrolling the electric motor to rotate the torque-transmitting coilaccording to the selected rotational speed setting.
 14. The method ofclaim 13, further comprising adjusting a guidewire brake actuatordisposed along the rear portion of the outer handle housing toreleasably lock the guidewire when the guidewire is positioned in therear guidewire port accessible along the rear portion of the outerhandle housing.
 15. The method of claim 14, the user interfaceaccessible along the upper exterior face of the outer handle housingfurther includes: a guidewire brake light indicator positioned rearwardof the fluid delivery button, wherein the controller assembly housedwithin the outer handle housing controls illumination of the guidewirebrake light indicator in response to movement of the guidewire brakeactuator disposed along the rear portion of the outer handle housingbeing moved to a locked position.
 16. The method of claim 11, whereinboth the atherectomy activation button and the electric motor arecarried by a carriage that is arranged within the outer handle housingand that is movable relative to the outer handle housing so as tolongitudinally translate the torque-transmitting coil within the centrallumen of sheath.
 17. The method of claim 11, wherein a rear guidewireport accessible along a rear portion of the outer handle housing isconfigured to receive a proximal portion of the guidewire while a distalportion of the guidewire extends distally of the torque-transmittingcoil.
 18. The method of claim 11, wherein the torque-transmitting coilterminates at a concentric metallic tip mounted to a distal-most end ofthe torque-transmitting coil, the concentric metallic tip having anannular body that extends distally from the torque-transmitting coil andan exterior tip diameter smaller than an exterior coil diameter of thetorque-transmitting coil, wherein the concentric metallic tip has acentral opening to receive the guidewire and has an exterior surfacethat is smoother than the eccentric abrasive element.
 19. The method ofclaim 11, wherein the at least one eccentric abrasive element comprisesa first eccentric abrasive element, further comprising at least a secondeccentric abrasive element spaced distally apart from the firsteccentric abrasive element along the torque-transmitting coil.